I know. It's really shit engine, unoptimized, gets locked on few thousand polygons, has shitty extent calculations, uses tiles instead of splats, the higher res textures blur easily, doesn't support animation combining, blah blah.
It's just impossible, not to mention they have redone the graphics engine TWICE for wc3 only, how much sense would it make to use the same graphic engine on two games? Well, that sorta happened with SC1 and WC2, but still, those games were RTSes, had same graphics, and were released in the same time.
That makes no sense, wow and wc3 graphics are totally different, both on technical, and art basis. However, you can easily tell that wow models were made long before wow (some of them, that is), cause they are used in campaign screens, and stuff like that. But still, they are not wc3 models, they are just wow models imported into wc3. Now you'll say it's easy to convert wow models to wc3, no it isn't, they just exported from .max to .mdx using art tools, instead exporting to .m2.